1.3 2

• Nucleotide


  The monomer unit that makes up nucleic acids
• Nucleic acids are polymers, made of many nucleotide monomer units
• Nucleic acids carry all the information needed to form new cells
• DNA


  Deoxyribonucleic acid, the genetic information is stored in the form of a code in the molecules of DNA
• mRNA


  Messenger RNA, parts of the code are copied into it and used to direct the production of proteins
• Eukaryotic cells


  • Genetic information is stored in chromosomes in the nucleus
• Prokaryotes


  • A single length of DNA is found floating freely in the cytoplasm
• Building polynucleotides


  1. Nucleic acids are chains of nucleotides linked together by condensation reactions that produce phosphodiester bonds

  2. The sugar of one nucleotide bonds to the phosphate group of the next nucleotide

  3. Polynucleotides always have a hydroxyl group at one end and a phosphate group at the other
• DNA


  Long chains of nucleotides containing the bases C, G, A and T
• RNA


  Chains of nucleotides containing C, G, A and U
• DNA molecule


  • Consists of two polynucleotide strands twisted around each other
  • The sugars and phosphates form the backbone
  • The bases pair up in specific ways - A with T, C with G
• DNA double helix


  • Resembles a spiral staircase
  • The two strands are held together by hydrogen bonds between the complementary base pairs
  • There are 3 hydrogen bonds between C-G and 2 between A-T
  • There are 10 base pairs for each complete twist of the helix
  • The two strands are known as the 5' and 3' strand
• The features of the structure of DNA and RNA are crucial to the way the molecules function within cells
• The Human Genome Project identified all the genes in human chromosomes and sequenced the 3 billion base pairs of human DNA
• The 1000 Genomes Project analysed the DNA of 1092 people from around the world to gain information about differences in DNA that can impact diseases
• The 10K Genomes Project is sequencing the genomes of 10,000 people with rare genetic diseases and cancers to increase understanding, diagnosis and treatment
• Phosphodiester bond


  The bond formed between the phosphate group of one nucleotide and the sugar of the next nucleotide in a condensation reaction
• Genome


  The entire genetic material of an organism